Name
uniq
Synopsis
uniq [options
] [file1
[file2
]]
Removes duplicate adjacent lines from sorted file1
, sending one copy of each line to file2
(or to standard output). Often used as a filter. Specify only one of -c, -d, or -u. See also
comm
and
sort
.
Options
- -c
Print each line once, counting instances of each.
- -d
Print duplicate lines once, but no unique lines.
-
-f
n
Ignore the first
n
fields of a line. Fields are separated by spaces or by tabs.-
-s
n
Ignore the first
n
characters of a field.- -u
Print only unique lines (no copy of duplicate entries is kept).
-
-
n
Ignore the first
n
fields of a line. Fields are separated by spaces or by tabs.-
+
n
Ignore the first
n
characters of a field. Both [-/+]n
have been deprecated but are still in this version.
Examples
Send one copy of each line from list
to output file list.new(list
must be sorted):
$ uniq list list.new
Show which names appear more than once:
$ sort names | uniq -d
Show which lines appear exactly three times:
$ sort names | uniq -c | awk '$1 = = 3'
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